Add the rolled oats, cold water, maple syrup (if using), vanilla extract (if using), and salt to a high-speed blender.
Blend on low speed for 30 to 60 seconds.
Pour the mixture into a nut milk bag or flour sack towel set over a large bowl or measuring cup. Gently squeeze to extract as much oat milk as possible, leaving the oat pulp behind.
Transfer the oat milk to a clean glass jar or bottle.
Refrigerate for up to 5 to 7 days. Shake well before serving, as natural separation will occur.
Notes
Cold water helps produce a smoother oat milk with a less starchy texture.
Pure maple syrup and pure vanilla extract are optional and can be adjusted or omitted to suit your taste.
Store the oat milk in a sealed container in the refrigerator for up to 5 to 7 days.
Natural separation is normal. Shake well before each use.